Besides replacing tents with some 1,000 residential containers on eight official sites, UNHCR is also delivering up to 200,000 winter items to 38,000 asylum-seekers on sites in the Greek mainland and the islands.

With his youngest son Yusef in his arms, Syrian refugee Monzir has reached safety in Greece but says he worries about what the EU-Turkey will mean for his family's future.

@ UNHCR/H. Holland

In the early hours of a March morning, Monzir's rubber dinghy arrived in Lesvos, but it was already too late. At midnight that day (March 20), the status of arrivals like Monzir underwent a seismic shift.

Two refugee women sit in-front of small camping tents in which they sleep near the village of Idomeni on the Greek border with the former Yugoslav Republic of Macedonia.

@ UNHCR/A.Zavallis

Urging caution, UNHCR today called on all parties to the recent agreement between the EU and Turkey on refugees and migrants to ensure all "safeguards" are in place before any returns from Greece to Turkey begin.

Europe is on the cusp of a largely self-induced humanitarian crisis in light of a rapid build-up of people in an already struggling Greece, with governments not working together despite having agreements in a number of areas.

Of the 660,000 refugees and migrants who have reached Greece this year more than half have landed at Lesvos. With winter approaching, reception conditions and capacity remain overstretched and inadequate.